There was a board I was looking to buy that I could potentially get a significant discount on, but it has a bit of damage to the tail as seen in the below pic. Does that need to be repaired or is it purely cosmetic? If it should be repaired how much $ am I looking at?

it's a little hard to tell from the picture but i would say all you need is to slap enough epoxy in there to seal up the core and just let it dry.

at most you might need to vice grip it down if the edge and top sheet are separated but it doesn't look that bad from the pic.

if there is a gap you can use something like a tooth pick to push some of the epoxy inside of it, spread a little more over it, then grip it down. you can use pieces of card board to protect your top sheet and base when using vices.